Background:Glioblastoma(GBM)is largely refractory to antibodies against programmed cell death 1(anti-PD-1)therapy.Fully understanding the cellular heterogeneity and immune adaptations in response to anti-PD-1 therapy ...Background:Glioblastoma(GBM)is largely refractory to antibodies against programmed cell death 1(anti-PD-1)therapy.Fully understanding the cellular heterogeneity and immune adaptations in response to anti-PD-1 therapy is necessary to design more effective immunotherapies for GBM.This study aimed to dissect the molecular mechanisms of specific immunosuppressive subpopulations to drive anti-PD-1 resistance in GBM.Methods:We systematically analysed single-cell RNA sequencing and spatial transcriptomics data from GBM tissues receiving anti-PD-1 therapy to characterize the microenvironment alterations.The biological functions of a novel circular RNA(circRNA)were validated both in vitro and in vivo.Mechanically,co-immunoprecipitation,RNA immunoprecipitation and pull-down assays were conducted.Results:Mesenchymal GBM(MES-GBM)cells,which were associated with a poor prognosis,and secreted phosphoprotein 1(SPP1)+myeloid-derived macrophages(SPP1+MDMs),a unique subpopulation of MDMs with complex functions,preferentially accumulated in non-responders to anti-PD-1 therapy,indicating that MES-GBM cells and SPP1+MDMs were the main anti-PD-1-resistant cell subpopulations.Functionally,we determined that circular RNA succinate dehydrogenase complex assembly factor 2(circSDHAF2),which was positively associated with the abundance of these two anti-PD-1-resistant cell subpopulations,facilitated the formation of a regional MES-GBM and SPP1+MDM cell interaction loop,resulting in a spatially specific adaptive immunosuppressive microenvironment.Mechanically,we found that circSDHAF2 promoted MES-GBM cell formation by stabilizing the integrin alpha 5(ITGA5)protein through N-glycosylation.Meanwhile,the N-glycosylation of the ITGA5 protein facilitated its translocation into exosomes and subsequent delivery to MDMs to induce the formation of SPP1+MDMs,which in turn maintained the MESGBM cell status and induced T-cell dysfunction via the SPP1-ITGA5 pathway,ultimately promoting GBM immune escape.Importantly,our findings demonstrated that antibody-mediated ITGA5 blockade enhanced anti-PD-1-mediated antitumor immunity.Conclusions:This work elucidated the potential tissue adaptation mechanism of intratumoral dynamic interactions between MES-GBM cells,MDMs and T cells in anti-PD-1 non-responders and identified the therapeutic potential of targeting ITGA5 to reduce anti-PD-1 resistance in GBM.展开更多
基金supported by grants from the National Natural Science Foundation of China(No.82473403,82273286,82273195)the Fundamental Research Funds for the Central Universities(2022JC019)+3 种基金Jinan Science and Technology Bureau of Shandong Province(2021GXRC029)Natural Science Foundation of Shandong Province of China(ZR2021LSW025,ZR2023LZL004)Taishan Pandeng Scholar Program of Shandong Province(tspd20210322)Youth Taishan Scholar Program of Shandong Province(tsqn202211316).
文摘Background:Glioblastoma(GBM)is largely refractory to antibodies against programmed cell death 1(anti-PD-1)therapy.Fully understanding the cellular heterogeneity and immune adaptations in response to anti-PD-1 therapy is necessary to design more effective immunotherapies for GBM.This study aimed to dissect the molecular mechanisms of specific immunosuppressive subpopulations to drive anti-PD-1 resistance in GBM.Methods:We systematically analysed single-cell RNA sequencing and spatial transcriptomics data from GBM tissues receiving anti-PD-1 therapy to characterize the microenvironment alterations.The biological functions of a novel circular RNA(circRNA)were validated both in vitro and in vivo.Mechanically,co-immunoprecipitation,RNA immunoprecipitation and pull-down assays were conducted.Results:Mesenchymal GBM(MES-GBM)cells,which were associated with a poor prognosis,and secreted phosphoprotein 1(SPP1)+myeloid-derived macrophages(SPP1+MDMs),a unique subpopulation of MDMs with complex functions,preferentially accumulated in non-responders to anti-PD-1 therapy,indicating that MES-GBM cells and SPP1+MDMs were the main anti-PD-1-resistant cell subpopulations.Functionally,we determined that circular RNA succinate dehydrogenase complex assembly factor 2(circSDHAF2),which was positively associated with the abundance of these two anti-PD-1-resistant cell subpopulations,facilitated the formation of a regional MES-GBM and SPP1+MDM cell interaction loop,resulting in a spatially specific adaptive immunosuppressive microenvironment.Mechanically,we found that circSDHAF2 promoted MES-GBM cell formation by stabilizing the integrin alpha 5(ITGA5)protein through N-glycosylation.Meanwhile,the N-glycosylation of the ITGA5 protein facilitated its translocation into exosomes and subsequent delivery to MDMs to induce the formation of SPP1+MDMs,which in turn maintained the MESGBM cell status and induced T-cell dysfunction via the SPP1-ITGA5 pathway,ultimately promoting GBM immune escape.Importantly,our findings demonstrated that antibody-mediated ITGA5 blockade enhanced anti-PD-1-mediated antitumor immunity.Conclusions:This work elucidated the potential tissue adaptation mechanism of intratumoral dynamic interactions between MES-GBM cells,MDMs and T cells in anti-PD-1 non-responders and identified the therapeutic potential of targeting ITGA5 to reduce anti-PD-1 resistance in GBM.
